System of communication



JulyZl, 1942.- e. 9. SMITH SYSTEM OF COMMUNICATION Filed March 20, 1941 2 Sheets-Sheet 1 SUBSCRIBER 75 :6 L To 36 suascmaea 1B a a e. a F

FRERMPLIFIER I67 IBI. l

UWL

I NV ENTOR. 65mm 6. 5/7/7776 BY July 1942* M G, 0. SMITH 2,290,817

SYSTEM OF COMMUNICATION Filed March 20, 1941 2 Sheets-Sheet 2 INVENTOR. 615mm 6. 5mm.

Patented July 21, 1342 ii: sr

parser SYSTEM OF CGMMUNICATEGN Gerald G. SmithyKenmore, N. Y asslgnor to 'ihe Rudolph Wurlitzer Gompany, iiincinnati,

Ohio, a corporation Application March 20, 1941, Serial No. 384,253

15 Olaims.

from one type of control to the other cannot beconveniently made simultaneously for all subscribers stations served by a single central stadescribed in Hayslett and Schmidt Patent No. 2,-

241,663, issued May 13, 1941, but is useful in other types of systems, as for example, that disclosed in Adrian PatentNo. 2,122,550, issued July 5, lat-l.

In systems of this type there is provided a central station and a plurality of subscriber's stations, the central station having one or more phonograph reproducer mechanisms and the subscribers stations having speakers which may be connected to a central station reproducer preferably in response to coin signals. In the Hayslett and Schmidt system disclosed in the copending application previously mentioned, twoway voice transmission is provided and a central station operator manually operates a number of phonograph mechanisms to supply each subscriber station with such music as the customers may call for by voice. Each subscribers station, in addition, is provided with a fully equipped record-changing phonograph mechanism to be used during hours when the central station operator is oiT duty. In the system disclosed in the Adrian patent before mentioned, no central station operator is employed and the operation of the central station phonograph is completely automatic and non-selective.

One object of the present invention is to provide a relatively simple system in which a central station reproducer may be automatically operated to supply a plurality of speaker in the subscriber's stations so arranged that each-subscriber receives full value .for each coin deposited.

,When used in a purely automatic system, such as disclosed in the Adrian patent, the present invention provides a much simplified and more sat sfactory operation-than that of the Adrian tion. The reason for this is the fact that when it is time for the operator to come on duty some stations may be operating on automatic control and their operation should not be disturbed but other stations not so operating should be immediately prepared for selection by voice. Slmi-= larly, when it is time for the operator to go ofi duty, some stations may be operating on manual control and stations not so operating should be immediately prepared for automatic operation without disturbing the manually controiiedop= eration then in progress. Thus, it is necessary to arrange the system in such manner that auto= matic and manual operation of different subscribers stations may take place simultaneously. The present invention provides a simple and com venient method for attaining this object.

In the 'Adrian patent before mentioned, means are provided for insuring full value for coins received at one station during the time that the central station reproducer is operating to supply the requirements of another station. This means in the Adrian patent requires the generation of additional coin value impulses to provide for this contingency. One object of the present invention is to eliminate the necessity for such additional impulses and so to simplify the apparatus required.

Other objects and features of the invention will be understood from the accompanying drawings and the following description and claims:

Fig. 1 is a wiring diagram of electrical parts and connections of a central station employed in a. preferred form of the invention. Fig. 2 is a similar diagram for one of the subscribers statioris.

In the drawings and in the following description the invention is described as applied to a system of the l -layslett and Schmidt type in which a central station operator is employed. Since the application of the invention to a fully automatic system requires only the elimination of the parts not required'for the manual operation, the construction and operation of a fully automatic system in accordance with the invention will be obvious.

Central station apparatus At the central station, there are provided a number of manually operated phonograph mech anisms corresponding to the number of suh scribers' stations to be served. Since these stations.

mechanisms are well known in the art, they are not shown in detail in the drawings. It is suflicient to say that each includes a turntable, mechanism for rotating the turntable and the usual stylus and pickup circuits. In the drawing the pickups 5 of two such mechanisms are shown diagrammatically.

There is also provided at the central station an automatic record changing phonograph reproducer unit which may be of any well known type. The parts of said mechanism which are pertinent to the invention are shown in the drawing enclosed within a brokenline indicated "Automatic reproducer" and consist of a pickup- 6, filter circuits l, a stage of amplification 8, a motor 9, a cam shaft and associated switches to be described hereinafter. The motor 9 may be the usual single motor used for operating the record changing mechanism and rotating the turntable and the cam shaft may be the usual one-revolution cam shaft used in mechanisms of this'type and which controls the record-changing'operation. In such mechanisms, the cam shaft normally makes one complete revolution for each record changing cycle and stops in a play position during the playing of a record. If the phonograph is to remain idle between the playing of records, the motor is stopped during the record-changing cycle with the cam shaft in an idle position. Usually the idle position of the cam shaft is reached after a record has been removed from the turnable and placed in the magazine and before another record has been removed from the magazine for playing. In the drawing a cam 2| carried by the cam shaft I0 is shown in full lines in the idle position. The position assumed by the nose of the cam in the playposition is shown in broken lines indicated Play."

There is also provided a central station transmitter ll having a pre-amplifier l2 associated therewith. Said transmitter and amplifier are employed in manual operation for transmitting the operator's voice to the various subscriber's A speaker l3 and monitor amplifier l4 are provided for reception and amplification of speech from the subscribers stations to the central station.

Each of the manually operated pickups 5 is are provided and each such device is associated.

with one of the subscriber's stations. Other central station apparatus includes a plurality of coin signal receiving units 20, each of which is adapted to receive coin signals from one of the subscribers stations and to transmit the same to the associated coin register l9 as will be described in more detail hereinafter.

Power for operating the central station isreceived from any suitable source on power mains 29 and 30 and preferably is the usual commercial 110 volt alternating current. One of said power mains has connected therein a cutout switch 3| and the other carries the usual overload fuse protection 32. .A transformer 33 has its primary winding connected to the mains 29 and 3D and has a secondary winding 34 providstation. The connection of the cathode heaters maybe conventional and for that reason is not shown in the drawings. Direct current is supplied to a pair of distributory conductors 36a and 361) from a secondary winding 31 of transformer 33 connected through a conventional rectifier unit 38. Said distributory conductors are grounded through resistors 39 and 40 respectively. Resistor 39 is proportioned to maintain the "conductor 36a at a suitable positive potential to supply plate current for the several amplifier units and to operatecertain direct current relays. Resistor 40 is proportioned to maintain conductor 36b at a' negative potential of a few volts.

Subscribers station electrical apparatus bersstation, power for operating the station is supplied by a pair of power mains and 48 connected to any suitable source, preferably 110 volt, alternating current. One of said power mains is provided with a cutout switch 41 and the other carries a protecting fuse 48. Said power mains areconnected to the primary winding of a transformer 50 and said transformer is equipped with a secondary winding 5| adapted to supply low voltage alternating current for heating the cathodes of vacuum tubes used in a local microphone pre-amplifier 52 associated with a local microphone 49. The transformer 50 is provided with a secondary winding 54 connected to a rectifier tube 55 supplying direct current at a suitable potential above ground to a conductor 56. Within the pre-amplifier 52 suitable plate voltages are secured byconventional connections to the. conductor 56. Other apparatus at the subscribers station includes an amplifier 51, a speaker 58 and a coin switch 59, The coin switch may be of any well known type adapted to make 'a momentary closure between a pair of ing alternating current at a low voltage suitable for heating the cathodes of the vacuum tubes used in the various amplifiers at the central conductors 60 and SI each time a coin of a given value is received thereby. The type of switch in which multiple momentary closures are made in response to coins of greater value may also be used. The construction and operation of such switches are well known in the art and need not be described in detail.

Wiring and operation The wiring connections shown in Figs. 1 and 2 may best be described in connection with a description of the operation of the apparatus.

Manual phonograph transmission from central station 'The output of each of the pickups 5 at the central station is amplified by its associated amplifier l6 which is coupled to the volume control rheostat l1 through a coupling condenser 62 and a two-way switch 63 operated by a relay 64 and normally maintained in the position shown in Fig. 1 when said relay is deenergized. The output of the amplifier stage I8 is impressed on the primary. winding of an output transformer 69. The secondary winding 10 of said transformer has its terminals connected to a pair of conductors H and 12 leading to the corresponding subscriber's station. The volume of the output impressed on the conductors H and 12 is controlled by the volume control rheostat I1.

At the subscriber's station the conductors II and l2are connected to the terminals of the primary winding 14 of an input transformer 15. The secondary winding 16 of said transformer has one terminal grounded and the other terminal connected through a series of resistance units II to the amplifier i. and speaker 58. The function of the resistance units I1 is to modify the output received -'from the transmission lines ii and I2 to give it substantially the same characteristics as the output of a phonograph pickup, so that a standard phonograph amplifier may be used at 51.

By means of these connections each of the phonograph pickups 5 at the central station is connected by a two-wire metallic circuit to the Voice transmission, central station to subscribers station The output of the central stationtransmitter II is amplified by its pre-amplifier I2. One of the output terminals of said Dre-amplifier is connected through a normally open switch operated by a key 82 to a bus line 9t and the second of said terminals is connected to a bus line 95. Saidbus lines may be selectively connected to the conductors II and I2 of any given subscriber's station by operation of normally open switches controlled by push buttons 99, one of said push buttons being provided for each of the subscribers stations. The push buttons 99 are mechanically interlocked in a Well known manner so as to be mutually exclusive. button when pressed is latched in position to connect its associated subscribers-station to the bus lines 89 and 95 and automatically releases to'the normal position any of said push buttons which have been perivously pressed. The volume of the output is controlled by suitable volume control means associated with the preamplifier I2. A meter 89 is connected across the bus lines 94 and 99 to indicate the energy level of the output to whichever subscriber's station is connected to said bus lines.

By means of the connections just described. the

' amplified output of the central station transmitter may be impressed on the two-wire metallic circuit leading to any one of the subscriber's stav tions by operation of the appropriate push button 86 and the talking key 82.

The output of the subscribers station transmitter 49 is amplified by its pre-amplifier' circuits 52 and is fed to the primary winding of an output transformer 99, the secondary winding of which has one terminal connected to the 'midpoint of the winding M of transformer and the other terminal grounded through a condenser 9| having proper capacity for freely transmitting alternating current of audible frequencies. At the central station the mid-point of winding .19 of each transformer 99 is connected to one terminal of the primary winding 92 of a transformer 93, the opposite terminal of which is grounded. The connections just described will be recognized as a grounded half phantom circuit That is, each push transformer 93 is connected through a condenser 94 and a normally open switch controlled by push button 99.to a bus line 95 which is grounded through a resistance 96 anda potentiometer 91. The opposite terminal is connected to ground through the distributory conductor 36b and resistance 49 to complete a secondary circuit. The potentiometer 91 controls the volume input to the amplifier I4 and speaker I3. The volume level is indicated by a meter 99 connected across the potentiometer 97. Said volume level is also controlled by a resistor 99 shunted across the potentiometer 91 by operation of the talking key 82 as described in the Hayslett and Schmidt application before mentioned.

By means of these connections the output of any one of the subscribers transmitters may be connected to the central station speaker I3 by operation of the proper push button 86.

Coin signal transmission The conductors 69 and bi at each subscriber's station are connected respectively to the midpoint of transformer winding I I through the secondary winding of transformer 99 and to one terminal of a secondary winding I99 of transformer 59, the opposite terminal of which is grounded. By this means the operation of the coin switch when momentary connection is made between the conductors 69 and GI impresses on thehalf phantom transmission circuit to the central station a signal in the form of an alternating voltage having the frequency of the alternating current power supply.

At the central station the incoming low free quency coin signal is transmitted to the secondary circuit of transformer 93 in the same manner as the incoming voice signals but the coin signal is preventedwfrom reaching the amplifier It by a reactance unit IM and condenser I92 connected in series across the input lines to said amplifier and serving to filter out the lower frequencies. A reactance I93 and a condenser I94 connected in series across the secondary terminals of transformer 93 serve as a low pass filter to transmitthe coin signal to a tube I95 having suitable electrodes andconnections for both rectification and amplification. The output circuit of said tube receives plate voltage from the positive di-- rect current distributory conductor 39a which is connected to the amplifier anode of said tube through the winding of electromagnetic relay I98.

in which alternating current energy induced in a the secondary winding of transformer 99 is transmitted over conductors Ii and F2 in parallel, through windings I9 and 92 to ground and returns through ground and condenser 9I to transformer 99.

One terminal of the secondary winding of .Said relay, therefore, is momentarily actuated each time a coin signal is received from the associated subscribers station.

; Each actuation of the electromagnet I98 momentarily closes a pair of normally open switches H2 and H3. The operation of the switch II2 completes a circuit from the alternating current power mains 29 and 39 for operation of an electromagnet II 4 which forms a part of the coin register device I9. Said device includes a ratchet wheel '5 normally urged in the clockwise direction by a coil spring H6 and held in position by an escapement Ill operated by a check-off magnet H8. The ratchet wheel II 5 is moved against the action of the spring I I6 by operation of the magnet II4, said movement being the equivalent of one tooth for each such actuation. Similarly, each actuation of the check-off magnet H8 operates the escapemerit II! to permit the ratchet wheel to return a distance corresponding to one tooth.

The ratchet wheel II5 carries a grounded contact member I29 .adapted to engage a contact segment I2l. In the normal idle position of the apparatus when no coin signalshave been received from the subscribers station, the contact member I20 is out of engagement with the contact segment I2l as shown in the drawing. When one or more coin signals have been received, the ratchet wheel I I5 is moved to engage the contact member 620 with the segment I2I and said engagement is maintained until a corresponding number of actuations of the check-oil? magnet II8 have been made. In manual operation, the

. check-oil magnet H8 is operated by a manual push button I22 which completes a circuit forsaid magnet from the power mains 29 and 30-.

In automatic operation the check-off magnet I I8 is operated by other means to be hereinafter described. Y

The engagement of contact members I20 and I2I completes a circuit for a pair of signal lamps I23, said circuit leading from a secondary winding I24 of transformer 33 through a conductor I to said lamps and then through said contact members to ground and to a grounded terminal of winding I24. The signal lamps I23 are used as described in the co-pending application of Hayslett and Schmidt, heretofore mentioned, to indicate to the operator the fact that'coin values have been registered and have notbeen checked 7 off. The position of the ratchet wheel I I5 ismade apparent to the operator by a suitable indicating push button 86 and through a normally open.

switch operated by said relay to the relay itself. Said relay thus remains energized after a momentary actuation of relay I08 until the corresponding push button 86 has been pressed. Said relay when actuated completes a circuit for a signal lamp I40 from the low voltage alternating current power main I25. The lamp I40 when lighted indicates to the operator that a coin value has been received at the corresponding station and that the corresponding push button 86 has not yet been pressed for the purpose of answering the call.

Re'sum of manual operation In the manual operation of the apparatus so far described, the receipt of a coin at any subscribers station causes the corresponding lamps I23 and I40 to be lighted at the central station. The operator then presses the corresponding push button 85, extinguishing the lamp I40, connecting the subscribers transmitter 49 to the central station speaker I3 and conditioning a circuit for connection of the central station transmitter II to the subscriber's speaker 58. The operator at the same time may operate the key 82 to complete the last named connection. The operator then requests the customer to name his choice of music and the customer answers by speaking into his transmitter 49. When the customer has named the selection or selections he desires, the operator manually starts the corresponding phonograph mechanism and checks oil one'coin value by operating the corresponding switch I22. The key 82 and the push button 86 may then be released.

circuit leading from ground- Automatic central station operation Several types of automatic central station operation are possible with the arrangement disclosed in Fig. 1. The automatic reproducer mechanism may be operated intermittently in response to the registry of coin values on the several coin register units I9, said mechanism resting in the idle position when no such coin values are registered. Or, for installations involving a large number of subscriber's stations where the reproducer would normally operate almost continuously, the circuits by which the register units-control the operation of the reproducer may-be omitted and the motor 9 'may be operated continuously to run the mechanism continuously through successive cycles of operation. In either case, the connection of the several subscribers speakers to the automatic reproducer mechanism is controlled by their corresponding register units. I9.

The several speakers maybe connected to the reproducer unit at the instant a coin. value is registered on their corresponding register units.

25 In that event a coin value registered at one station during the playing of a record called for by another station makes it possible for the remaining fraction of the record to be heard at the first mentioned station in addition to the full record called for by its own coin value. In the alternative, the speaker connection may be delayed until the playing period is completed, when only the full record called for by the coin value will be heard. The former mode of operation may be called the "method of audible fractions and the latter mode may be called the "method of silent fractions. Either of these methods may be used with either continuous or intermittent motor operation. I

Speaker connections nections for-the method of silient fractions will firstbe described.

There is provided on each of the coin register devices I9 a switch I45 which is opened by the v contact member I20 when the register device has no coin values registered thereon but which is closed when one or more coin values have been registered/but have not been checked oil. Said switch is included in a circuit for actuating the corresponding relay B4. Said circuit leads from the power main 29 through a phonograph operated switch I46, a bus line I", the switch I45,

the snap switch III, and a switch I49 operated by relay 84 to the coil of said relay and thence through a bus line I50 and a phonograph operated switch I5I to the power main 30. circuit the switch I46 is closed only when the phonograph mechanism is in or passing through the idle position. The switch I5I is normally closed and is opened momentarily at any convenient point in the cycle of phonograph operation after a record has been played and before the mechanism reaches the idle position. The switch MI is closed whenever automatic opera- In this tion is .desired and is opened when the corresponding subscriber's station is to be supplied by manual control. The switch are is normally in the position shown in the drawing when the relay 66 is deenergized but is provided with a front contact connected to a branch of the power main 29. Switch iii is so adjusted that the front contact is made before the back contact is broken. By means of this-circuit each relay. to is energized when a'coin value is registered on a corresponding register device it provided that the phonograph mechanism is in the idle position. The actuation of relay ea closes the front contact of switch I49 and thus retains the magnet thereafter irrespective of the position of switches it? and M6. Each relay fit remains energized until the retaining circuit therefor is the record has started, its speaker is connected for the remaining fraction of the record but the coin value is not checked off until the start of the next record. In the interim said coin value has been effective to reconnect the speaker after broken by the opening of switch it! after a record has been played. The operation of each relay M actuates the corresponding switch E3 to disconnect the subscriber's line from th manual pickup '5 and to connect the same to the automatic reproducer pickup 6 through a bus line I52, a coupling condenser I53, the amplifier 8 and the filter circuits i. I

By means c the connections just described it will be apparent that connections may be established between the subscriber's speakers and the automatic reproducer unit only when a coin value has been recorded on the corresponding coin register unit l9 and when the reproducer mechanism is in or passing through the idle position.

A coin value registered after the idle position is passed has no effect in connecting the speaker. When once connected'the speakers remain connected irrespective of the position of the coin register devices 89 until the switch E58 is opened momentarily after the play of a record. When the idle position of the apparatus is again reached, only such speakers as still have coin values registered on their corresponding units 39 are reconnected to the phonograph.

For operation by the method of audible fractions, the switch M2 is closed and the switch lit is thus short circuited. Under these conditions, the circuits previously described for actuating the relaysi i may be completed at any time that a Check 01? circuits For automatically checking off coin values on the several coin register units it there is provided a phonograph operated check-off switch I51 which is momentarily closed at a convenient time in the cycle of phonograph operation. The switch l5? has one terminal connected to a branch of the power. line 29 and the opposite terminal connected to a bus line E58. Each of the relays Ed is provided with a switch 559 connected to said bus line and to the corresponding check-off magnet H8 through a back contact of the manual check-off push button 822. By means of this arrangement, the check-off magnet H8 corresponding to each subscribers station whose speaker is connected to the automatic phonograph mechanism is actuated when switch it? is closed.

When the method of audible fractions is used it is important that the check-off switch id? be switch it! has been actuated. Preferably the.

check-off switch. I5? is operated during the movement of the cam shaft It Just before the playing position is reached; It sometimes happens that the mechanism is designed so that the cam shaft movement continues for a short time after the playing of the record is started. It is therefore possible that the check-off may occur slightly after the start of play. This is not objectionable since a speaker connected at that time will receive. substantially a complete record in return turned to its normal closed position after an actuation thereof.

Motor circuits For intermittent operation of the motor 9 the starting of the motor may-be controlled directly from suitable switches operated by the coin register units i9 or may be controlled by said register units through the action of the relays 64 as illustrated in Fig. 1. Each of said relays operates a normally open switch Hit connected between a branch of the power main 29 and a bus line H65 leading to one terminal of the motor 9. The opposite terminal of the motor is connected to power main 30. Thus the operation of any of the relays 64 starts the motor and moves the cam shaft [0 away from the idle position. The first movement of the'cam shaft closes'a switch fled which is open in the idle position only and which is connected in parallel with the switches ltd.

The operation of said switch thus retains the motor circuit through a complete cycle of operations independent of the relays 64. At the end of said cycle, the switch N36 is opened and the motor is stopped unless there is a coin value registered and one of the relays 64 is energized as a result thereof. In'the latter case another cycle of operations is immediately initiated.

For continuous motor operation a snap switch I6! is closed to connect the motor 9 directly across the power mains 29 and30. When the system is to be used with continuous operation only, the switches 194 and associated wiring may be eliminated and the switch I6? is then used to stop the motor when all stations have been. re-

turned. to manual control and to start the motor when automatic operation is again desired.

Re'sume' of automatic central station operation When it is desired to change from manual to automatic central station operation, a choice may be made between intermittent and continuous motor operation and between the methods of audible fractions and silent fractions. If intermittent motor operation is to be used, switch it! is left open. If continuous operation is to be used, switch I67 is closed, but need not be closed before one or more of the subscribers stations have been switched to automatic control. For the method of silent fractions, switch I42 remains open. For audible fractions, switch I 42 is closed. For any of the several types of operation, the snap switches I4I are individually closed to provide automatic operation as the manual operations of the associated stations are completed. Thus some stations may be operating on automatic control while others are still operating manually. The switches I4I are included in the .circuits used to establish connections for the re:

lays 64 and said relays can not be energized while said switches are open. Since the relays 64 control the speaker connections to the automatic reproducer, the motor starting circuits (in intermittent operation) and the automatic check-01f circuits, the operation of one of the coin register devices while the corresponding switch I is open can not interfere with the speaker connection to the manual pickup or affect the operation of the automatic reproducers. Similarly, the

operation of the automatic reproducer can not affect the check-off magnets of those stations whose switches I4I are open. The provision of the back contacts in the manual check-off. switches I22 insures that an inadvertent operation of the switch I22 of a station operating automatically will effect a check-off on that station only and not on other stations then operating automatically.

Assuming operation by silent fractions (switch I42 open) and intermittent motor operation (switch I61 open), the automatic reproducer stands in the idle position when the first of the switches MI is closed. If one or more coin values are registered on one of the register devices I9 when th corresponding switch I is about the time that the actual play of a record commences, switch I51 is closed to check off a coin value from each register unit whose speaker is then connected to the automatic phonograph. Since the relays 64 of stations which have received coins after the phonograph mechanism was started are not energized such coin values will not be checked off at the start of play. After the playing of a record and before the idle position of the mechanism is reached, switch I5I is opened to deenergize all of the relays 64..

Motor operation continues since switch I66 is closed. If unsatisfied coin values are still. registered on any of the register units I9 when the idle position of the apparatus is reached, the operation of switch I46 immediately energizes the corresponding relays 64' and initiates another cycle of operation. If there are no such coin values registered, the operation of switch I66 when the idle position of the apparatus is reached opens the motor circuit and stops phonograph operation.

Assuming operation by audible fractions (switch I42 closed) and intermittent motor operation (switch I61 open), the start of operation is the same as just described for operation by silent fractions. When a coin value is registered after the phonograph mechanism has started the associated relay 64 is immediately energized through the closed switch I42 and the associated speaker is connected to the automatic reproducer. At or about the time that the actual play of the record commences, switch I5I- is closed to check off a coin value from each register unit whose speaker is then connected to the automatic reproducer. Since stations which have received coin values since the phonograph started are connected, coin values are checked off from such stations. The registry of coin values after the start of play similarly results in the actuation of the corresponding relays 64 so that the remaining fraction of the record is audible. Since the check off has already occurred such coin values are not checked off until the next operation. After the play of a record, switch I5I is momentarily opened to deenergize all of the relays 64. When switch I5 I is again closed all of said relays whose register units still have coin values registered thereon are reenergized and their speakers are again connected to the automatic reproducer. If there are any such relays energized when the idle position of the apparatus is reached, switch I66 is. ineffective to stop the motor and another cycle of operations is immediatelyinitiated.

Assuming continuous motor operation (switch I 6'! closed) the operation is the same as Just described except that cycles of phonograph operation follow each other automatically and continuously. The registry of coin values has the effect of connecting the speakers when the mechanism passes through the normal idle position for operation by silent fractions or connecting thespeakers whenever such coin values are registered in the method of audible fractions. The check-off is operated in the same manner as beore.

When it is desired to change a subscribers station from automatic to manual operation the corresponding switch I is opened. If the station is then operating automatically the opening of switch I4I has no effect since relay 64 remains energized by its stick circuit until the play of a record is completed and switch I5I is opened. When switch I5I is again closed, the open switch I prevents reenergizing of relay 64. Coin values remaining unsatisfied are indicated by the signal lamps I23 and 'may be satisfied manua y.

When continuous operation has been employed, the switch I61 is opened after all of the switches I4I have been opened. The motor continues to operate under control of switch I66 until the idle position is reached whereupon said switch is opened to stop the motor.

When the invention is to be used in a fully automatic system such as disclosed in the Adrian patent before mentioned, obviously much of the apparatus illustrated in the drawings may be eliminated. At the subscribers stations the microphones 49 and amplifiers 52 are not needed. At the central station the manual pickups 5 and associated circuits, the transmitter II, speaker I3 and amplifiers I2 and I4 may be. dispensed with and the connections of the automatic reproducer to the subscribers lines may be much simplifled. Even though the method of audible fractions is used, there is no necessity for additional coin impulses as in the Adrian apparatus.

The invention has been" described in one of its preferred forms, the details of which may be varied without departing from the scope of the invention as defined by the appended claims. The

subscriber's stations may be located in separate establishments in different parts of a city and may be connected to the central station bycomw, mercial telephone lines, permanently connected at the telephone central. In-the drawings the conductors H and i2 may be considered to be such commercial telephone lines. Alternatively the subscribers stations may be in difierent apartments of the same establishment-fore ample, the private dining rooms and bedrooms of ahotel or apartment house. In the claims the term subscriber's station is not to be considered as limiting such stations to separate establishments.

The invention claimed is I. In a communication system having a'phonograph reproducer 'at a central station and speakers at a plurality of subscriber's stations, coin register and check oii means associated with each subscriber's station and controlling the operation of the reproducer to initiate a cycle of operation thereof when one or more coin values have been registered and not checkedofi, and phono graph operated means for actuating said check off means at a time in the cycle of phonograph operation preceding the playing of a record,

whereby a coin value registered during the play ing of a record is not checked ofi until said record has been played and another cycle of phonograph operation has been initiated.

2. In a communication system having a phonograph reproducer at a central station and speakers at a plurality of subscribers stations, coin register and check off means associated with each subscriber's station and controlling the operation of the reproducer to initiate a cycle of operation thereof when one or moregcoin values have been registeerd and not checked'ofi, and

phonograph operated means ioractuating said check 03 means at approximately the beginning of play of the record, whereby .a coin value regisa. tered "during the playirg of a record is not checked ofi until saidrecord has been played and another cycle of been initiated. a

3. In a communication system having a phonograph reproduced at a central station and speakers at a plurality of subscriber's stations, coin register and check ofi means associated with each subscribers station and controlling the operation of the reproducer to initiate a cycle of operation thereof when one or more coin values have been registered and not checked ofi, and

phonograph operated means for actuating said phonograph operation has graph operated means for actuating said check ofi devices to check off a coin value on each of said devices having its speaker connected to said reproducer, said means being eiiective at a time in the cycle of phonograph operation preceding the playing of the record, whereby a coin value initiated.

5. In a communication system having a phonograph reproducer at acentral station and speakers at a plurality of subscriber's stations, a coin register and check ofi device associated with each subscribers station, electric circuits controlled by said devices and controlling the operation of said reproducer to initiate a cycle of operation thereof when a coin value has been registered on any one of said devices and not checked off, and to connect the reproducer to the speaker associated with the device having such coin value registered thereon, phonograph controlled retaining circuits adapted to retain said speaker connections through the complete playing of a record independent of said check off devices, and phonograph operated means for actuatingsaid check ofi devices to check off a coin value on each of said devices having its speaker connected to said reproducer, said means being effective at approximately the beginning of play of the record, whereby a coin value registered during the playing of a record is not checked off until said record has been played and another cycle of phonograph operation has been initiated.

6. In a communication system having a phonograph reproducer at a central station and speakers at a plurality of subscribers stations, a coin register and check off device associated with each subscriber's station, electric circuits concheck off means'and operative after a cycle of p operation has been initiated and before the playin of a recordhas progressed substantially beyond its starting point, whereby a coin value registered during at least the greater portion of the playing time of a record is not checked ofi until the playing of the record is complete and said coin value has been eifective to initiate another cycle of operation.

4. In a communication system having a phonograph reproducer at a centralstation and speakers at a plurality of subscribers stations, a coin register and check ofi device associated with each subscribers station, electric circuits controlled by said devices and controlling the operation of said reproducer to initiate a cycle of operation thereof when-a coin value has been registered on any one of said devices and not checked off, and to connect the reproducer to the speaker associated with the device having such coin value registered thereon, phonograph controlled retaining circuits adapted to retain said speaker connections through the complete playing of a record indetrolled by said devices and controlling the operation of said reproducer to initiate a cycle of operation-thereof when a coin value has been registered on any one of said devices and not checked oii, and to connect the reproducer to the speaker associated with the device having such coin value registered thereon, phonograph controlled retaining circuits adapted to retain said speaker connections through the complete playing of a record independent of said check ofi devices, and phonograph operated means for actuating said check off devices to check off a coin value on each of said devices having its-speaker connected to said reproducer, said means being effective at a time in the cycle of phonograph operation before the playing of a record has proa coin register and check oiT device associated -with each of said coin receiving devices and adapted to register the value of coins received thereby in terms of records to be played, electric "circuits controlled by said coin registers and adapted to initiate an operation of said phono graph unit when a coin value. has been registered on any one of said coin registers and not checked oil, and to connect said phonograph unit to the speakers associated with the coin registers having coin values registered thereon, electric circuits controlled by operation of said phonograph unit and adapted to operate at a point in the 'cycle of phonograph operation before play of the tions, an automatic record changing phonograph unit at said central station operable through successive cycles including periods of play'and intermediate periods during which records are changed, a coin register and check off device associated with each subscribers station, electrical apparatus controlled by said coin register devices and adapted to connect to said phonograph unit the speakers corresponding to the coin register units having coin values registered thereon,

phonograph controlled check off circuits operable before the record playing period has pro gressed substantially beyond its starting point and adapted to check off a coin value on each coin register device corresponding to a speaker then connected to said phonograph, and phonograph controlled retaining circuits adapted to retain said speaker connections through a complete playing period independent of said check 01!.

9. In a communication system having a central station and two or more subscribers stations, an automatic record changing phonograph unit at said central station operable through successive cycles including periods of play and intermediate periods during which records are changed, a coin register and check off device associated with each subscribers station, speaker connecting means controlled by said coin register devices and by said phonograph unit and adapted to establish connections between said unit and the speakers corresponding to such coin register devices as have coin values registered thereon, phonograph controlled circuit retaining means adapted to reta'n said speaker connections, said retaining means being effective from a predetermined point in the record changing period, through the'playing period and to a second predetermined point in the succeeding record changing period and being ineffective between said points, said speaker connecting means being effective to establish speaker connections during a part at least of the record changing period after said retaining means has become effective and being ineffective to establish such connections at least through the major portion of the playing period, and phonograph operated check oil circuits operating at a point in the cycle of operation when the speaker connecting means is ineffective to check off a coin value on each coin register device corresponding to a speaker then connecttd to said phonograph.

10. In a communication system having a central station and two or more subscribers stations, an automatic record changing phonograph unit at said central station operable through successive cycles including periods of play and intermediate periods during which records are changed, a coin register and check off device associated with each subscribers station, a

speaker operating stick relay associated with each subscribers station and each adapted when actuated to connect its associated speaker to the phonograph unit, actuating circuits for said relays each controlled by its associated coin register device to actuate said relay when acoin value is registered thereon, retaining circuits for said relays controlled by phonograph operation to retain said relays throughout the record playing period, and a check oiT circuit for each of said coin register devices, each such circuit being controlled by the associated relay and operated by said phonograph at approximately the starting point of the playing period to check off a coinvalue on each register device associated with an actuated relay. a 11 In a communication system having a central station and two or more subscribers stations, an automatic record changing phonograph unit at said central station operable through successive cycles including periods of play and intermediate periods during which records are changed, a coin register and check off device associated with each subscribers station, a speaker operating stick relay associated with each subscribers station and each adapted when actuated to connect its associated speaker to the phonograph unit, actuating circuits for said relay each controlled byits associated coin register device to actuate said relay when a coin value is registered thereon, retaining circuits for said relays controlled by phonograph operation, said retaining circuits being ineffective during a portion of the record changing period but efl'ective during the playing period and during a portion of the record ch'ang: ing period immediately preceding the playing period, said relay actuating circuits being controlled by phonograph operation so as to be efiective in at least a part of the last mentioned pcr-. tion of the record changing period but ineffective during the playing period, and a check off circuit for each of said coin register devices, each such circuit being controlled by theassociated relay and operated by the phonograph ata point in the cycle of operations when the relay actuating cir-,

cuits are ineffective, -to check ofi a coin value on each register device associated with an actuated relay.

'12. In a communication system having a cen-- mitter and a receiver at said central station, a

speaker, a transmitter and a coin receiving device at each subscribers station, electric circuits connecting said central station and said subscribers stations and normally connectingeach of said manual phonograph units to one of said subscribers speakers, and including keying means adapted selectively to connect the central station transmitter and receiver to the speaker and transmitter at any of said subscribers stations for two way conversation, and manually operated means at said central station associatedwith each of said subscribers stations and adapted to establish electrical connections by means of which the subscribers speaker may be connected to the automatic phonograph unit and said automatic phonograph unit may be controlled by the associated coin receiving device.

13. In a communication system having a central station and a plurality of subscribers stations, a plurality of manually controlled phonograph reproducer units, an automatic record changing phonograph reproducer unit, a transmitter and a receiver at said central station, a

speaker, a transmitter and a coin receiving de- -vice at each subsc'ribers station, electric circuits connecting said central station and said subscribers stations and-normallyconnecting each of said manual'phonograph units to one of said subscriber's speakers, and including keying means adapted selectively to connect the central station transmitter and receiver to the speaker and 'transmittervat any of said subscriber's stations for two way conversation, coin register and check oil devices at said'centrallstation each connected to and controlled by one of said coin receiving devices, and adapted to indicate to .an

operator the number-of coin values received at said station and-not'ch'ecked ofl, .manualcheck off transmitter and receiver to the speaker and trans-' mitter at any of said subscriber's stations for two way conversation, and manually operated means at said'central station adapted to establish electrical connections by operation of which the subscribers speakers maybe connected to the automatic phonograph unit and 'said automatic phonograph unit may be controlled by said coin receiving devices; v

15. In a communication system having a'central station and a, plurality of subscriber's stations, a plurality of manually controlled phonograph reproducer units, an automatic record changing phonograph reproducerunit, a transmitter and a receiver at'said central station, a speaker, a transmitter and a coin receiving de vice ateach subscribers station, electric circuits means for checking oil coin :values from said devices, automatic check 01! means operable by'said automaticphonograph to check 01! coin values from'said devices, said means being normally ineffective, and manually operated means associated with' each oifJsaid subscriber's stations and adapted to establish electrical connections by means ofwhich said automatic'phonograph unit may be connected to the-subscriber's speaker, and the correspondingccin register device may control the operatio'n'of said automatic phonograph unit andsaid automatic check off means is ren'-' clered efl ective.

14. In a communication system having a central station and .ja. plurality of subscriber's staconnecting said central station and said subscribers stations and normally connecting each of said manual phonograph units to one of said. subscriber's speakers, I means adapted selectively to connect the central station transmitterand receiver to the speaker and transmitter at any 'of'said subscriber's staofl! means for' checking. oil coin valuesfrom said tions, a plurality ofmanually controlled phonograph reproduceri units, an automatic record changing phonograph reproducer unit, a transmitter'anda receiver at said central station, a

speaker, a transmitter and-a coin receiving device at each subscribers station, electric circuits connecting said central station and said subscribers stations and normally connecting each of said'manual phonograph units to one of said subscriberfs speakers, and, including keying'means adaptedselectively to connect the central station tions for two way conversation, coin register and check off devices at said central station each connected'to and controlled by one of saidi'coin receiving devices,'and adapted. toindicate to an;

operator the number of coin values received at said station and not checked ofl',imanual check matic phonograph unit, said coin register devices may control the operation of said'automatic phonograph unit and said automatic check oi! means is rendered eflective.

and including keying'A G B G, 

